/*
 * ProGuard -- shrinking, optimization, obfuscation, and preverification of Java bytecode.
 *
 * Copyright (c) 2002-2018 GuardSquare NV
 *
 * This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later
 * version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
package proguard.obfuscate;

import proguard.classfile.*;
import proguard.classfile.util.*;
import proguard.classfile.visitor.MemberVisitor;

import java.util.Map;

/**
 * This MemberInfoVisitor solves obfuscation naming conflicts in all class members that it visits. It avoids names from
 * the given descriptor map, delegating to the given obfuscator in order to get a new name if necessary.
 *
 * @author Eric Lafortune
 */
public class MemberNameConflictFixer implements MemberVisitor {
    private final boolean allowAggressiveOverloading;
    private final Map descriptorMap;
    private final WarningPrinter warningPrinter;
    private final MemberObfuscator memberObfuscator;

    /**
     * Creates a new MemberNameConflictFixer.
     * 
     * @param allowAggressiveOverloading a flag that specifies whether class members can be overloaded aggressively.
     * @param descriptorMap the map of descriptors to [new name - old name] maps.
     * @param warningPrinter an optional warning printer to which warnings about conflicting name mappings can be
     *        printed.
     * @param memberObfuscator the obfuscator that can assign new names to members with conflicting names.
     */
    public MemberNameConflictFixer(boolean allowAggressiveOverloading, Map descriptorMap, WarningPrinter warningPrinter,
        MemberObfuscator memberObfuscator) {
        this.allowAggressiveOverloading = allowAggressiveOverloading;
        this.descriptorMap = descriptorMap;
        this.warningPrinter = warningPrinter;
        this.memberObfuscator = memberObfuscator;
    }

    // Implementations for MemberVisitor.

    public void visitProgramField(ProgramClass programClass, ProgramField programField) {
        visitMember(programClass, programField, true);
    }

    public void visitProgramMethod(ProgramClass programClass, ProgramMethod programMethod) {
        // Special cases: <clinit> and <init> are always kept unchanged.
        // We can ignore them here.
        String name = programMethod.getName(programClass);
        if (ClassUtil.isInitializer(name)) {
            return;
        }

        visitMember(programClass, programMethod, false);
    }

    public void visitLibraryField(LibraryClass libraryClass, LibraryField libraryField) {}

    public void visitLibraryMethod(LibraryClass libraryClass, LibraryMethod libraryMethod) {}

    /**
     * Obfuscates the given class member.
     * 
     * @param clazz the class of the given member.
     * @param member the class member to be obfuscated.
     * @param isField specifies whether the class member is a field.
     */
    private void visitMember(Clazz clazz, Member member, boolean isField) {
        // Get the member's name and descriptor.
        String name = member.getName(clazz);
        String descriptor = member.getDescriptor(clazz);

        // Check whether we're allowed to overload aggressively.
        if (!allowAggressiveOverloading) {
            // Trim the return argument from the descriptor if not.
            // Works for fields and methods alike.
            descriptor = descriptor.substring(0, descriptor.indexOf(')') + 1);
        }

        // Get the name map.
        Map nameMap = MemberObfuscator.retrieveNameMap(descriptorMap, descriptor);

        // Get the member's new name.
        String newName = MemberObfuscator.newMemberName(member);

        // Get the expected old name for this new name.
        String previousName = (String)nameMap.get(newName);
        if (previousName != null && !name.equals(previousName)) {
            // There's a conflict! A member (with a given old name) in a
            // first namespace has received the same new name as this
            // member (with a different old name) in a second name space,
            // and now these two have to live together in this name space.
            if (MemberObfuscator.hasFixedNewMemberName(member) && warningPrinter != null) {
                descriptor = member.getDescriptor(clazz);
                warningPrinter.print(clazz.getName(), "Warning: " + ClassUtil.externalClassName(clazz.getName())
                    + (isField ? ": field '" + ClassUtil.externalFullFieldDescription(0, name, descriptor)
                        : ": method '" + ClassUtil.externalFullMethodDescription(clazz.getName(), 0, name, descriptor))
                    + "' can't be mapped to '" + newName + "' because it would conflict with "
                    + (isField ? "field '" : "method '") + previousName + "', which is already being mapped to '"
                    + newName + "'");
            }

            // Clear the conflicting name.
            MemberObfuscator.setNewMemberName(member, null);

            // Assign a new name.
            member.accept(clazz, memberObfuscator);
        }
    }
}
